CN108025613B - Air suspension system - Google Patents

Abstract

The compressor (3) of the air suspension system is easily started under the condition that differential pressure exists. An air suspension system supplies air compressed by a compressor (3) to a plurality of air chambers (1C, 2C) interposed between a vehicle body side and a wheel side and performing vehicle height adjustment in accordance with supply and discharge of the air, wherein the compressor (3) has: a mover (36) that is coupled to the piston (34) and extends in the direction in which the piston (34) moves; and an armature (50) that reciprocates the mover (36) in the moving direction of the piston (34).

Description

Air suspension system

Technical Field

The present invention relates to an air suspension system.

Background

Patent document 1 discloses an air suspension system for adjusting the vehicle height by supplying and discharging air compressed by a compressor to and from an air suspension.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012 and 159011

Disclosure of Invention

Technical problem to be solved by the invention

The compressor compresses air drawn from the suction port and sends the compressed air to the discharge port. The compressed air sent to the discharge port flows into the air chamber from the discharge port, and the vehicle height can be raised. In general, in an air suspension system, since the pressure of the pipe on the discharge port side is maintained for reasons such as efficiency of vehicle height adjustment, a state (differential pressure state) in which the pressure on the discharge port side is higher than the pressure on the suction port side is likely to occur even in a state in which the compressor is not started. Here, in the compressor in the air suspension system of patent document 1, since the output of the rotary motor is converted into a linear motion by the crank mechanism, when the drive is stopped at or near the bottom dead center of the piston, if the compressor is to be restarted, the piston cannot move unless the air in the high-pressure compression chamber is further compressed, but the angular momentum of the rotary system including the counter weight immediately before the compression operation is small or absent, and therefore, a large driving force is required for the completion of the compression operation and the start.

In such a case, when the compressor is difficult to start because a large driving force is required, it is necessary to reduce the differential pressure by discharging the air or the like in the discharge-side pipe. However, if the discharge-side air is discharged, in order to raise the vehicle height again, the discharged amount of air must be compressed in the initial stage of driving the compressor, which leads to a decrease in the adaptability of the compressor and an increase in the energy consumption. Therefore, it is desirable to maintain the pressure in the air chamber and the ejection port on the ejection side.

The purpose of the present invention is to facilitate the starting of a compressor in an air suspension system under conditions where a differential pressure exists.

Means for solving the problems

The present invention made in view of the above circumstances relates to an air suspension system that supplies air compressed by a compressor to a plurality of air chambers that are interposed between a vehicle body side and a wheel side and that perform vehicle height adjustment in accordance with supply and discharge of the air, the air suspension system being characterized in that the compressor includes: a mover coupled to the piston and extending in a moving direction of the piston; and an armature that reciprocates the mover in a moving direction of the piston.

Effects of the invention

According to the present invention, it is possible to provide an air suspension system capable of easily starting a compressor under a condition where a differential pressure exists.

Drawings

Fig. 1 is a circuit diagram showing an air suspension system of embodiment 1.

Fig. 2 is a schematic diagram of a vehicle mounted with the air suspension system of embodiment 1.

Fig. 3 (a) is a yz plane sectional view of the compressor of embodiment 1, and (b) is a sectional view of the compressor based on a-a in fig. 3 (a), and is a z-direction view of the armature and the mover.

Fig. 4 is a plan view of the mover of embodiment 1.

Fig. 5 is a graph showing the relationship of the displacement of the piston, the force generated by the air pressure applied to the piston, the magnetic force, and the spring force with respect to time in embodiment 1.

Fig. 6 is a diagram showing the z-direction position of the piston of embodiment 1 and the relationship of the spring force applied to the piston, the force generated by the air pressure, and the magnetic force.

Fig. 7 is a sectional perspective view of the linear motor of embodiment 1 having 2 armatures and magnetic spacers disposed therebetween.

Fig. 8 is a view in which the magnetic force is removed from fig. 6.

Fig. 9 is a circuit configuration diagram of an air suspension system showing a valve switching state when raising the vehicle height in embodiment 1.

Fig. 10 is a circuit configuration diagram of an air suspension system showing a valve switching state when lowering the vehicle height according to embodiment 1.

Fig. 11 is a circuit configuration diagram of an air suspension system of embodiment 2.

Fig. 12 is a circuit configuration diagram of an air suspension system of embodiment 3.

Fig. 13 is a circuit configuration diagram of an air suspension system of embodiment 4.

Fig. 14 is a yz plane sectional view of the compressor of embodiment 5.

Fig. 15 is a yz plane sectional view of the compressor of embodiment 6.

Fig. 16 is a graph showing a relationship between a stroke command value L (a command value of the amplitude of the reciprocating motion of the mover or the piston), a frequency command value ω of the applied voltage to the coil, and an amplitude command value V of the applied voltage and time t in the entire normal state from the start of the compressor of example 6.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same components are denoted by the same reference numerals, and the same description will not be repeated. The present invention is not limited to the specific forms described in the embodiments.

The x, y, and z directions used in the description are orthogonal to each other.

Example 1

[ air suspension System 100]

Fig. 1 is a circuit diagram showing an air suspension system 100 according to embodiment 1, and fig. 2 is a schematic diagram of a vehicle 200 on which the air suspension system 100 is mounted. In the air suspension system 100 of fig. 2, only the distribution point 9N described later and the components on the air suspensions 1 and 2 side of the distribution point 9N are shown.

The air suspension system 100 has 2 air suspensions 1, 2, a compressor 3 having a linear motor 3B as a drive source, an intake air filter 4, a 1 st tank 5, an air dryer 7, and 3 check valves 8, 15, 17 as valves, a supply/ discharge switching valve 10, 2 suspension control valves 11, 12, a return passage opening/closing valve 14, and an exhaust passage opening/closing valve 19. The air suspension system 100 connects them with a passage through which air can flow.

The air suspension system 100 is mounted on, for example, a vehicle 200, and controls the air pressure in the air chambers 1C and 2C of the air suspensions 1 and 2. For example, an axle 220 connecting their hubs and the like to each other is provided at the left wheel 210L and the right wheel 210R of the vehicle 200. For example, the air suspensions 1 and 2 are provided between the vehicle body 230 and the wheel 210 side, such as between the vehicle body 230 and the left and right wheels 210L and 210R, respectively, and between the vehicle body 230 and the wheel hub, and the vehicle height can be adjusted by controlling the air pressure in the air chambers 1C and 2C.

The air suspensions 1 and 2 may be attached between an axle 220 on the wheel 210 side and a vehicle body 230 of the vehicle 200 as shown in fig. 2, or may be attached between an arm of a suspension that couples the wheel 210 and the vehicle body 230 (the wheel 210 side) and the vehicle body 230, or between a hub of the wheel 210 (the wheel 210 side) and the vicinity of a portion where the vehicle body 230 is attached to an upper arm of the suspension (the vehicle body 230 side). The air suspensions 1 and 2 may be provided to support the wheel 210 and the vehicle body 230 in this manner, and may be provided between the wheel 210 and the vehicle body 230 in the vertical direction, for example, and are not limited to the form of being directly attached to the wheel 210 and the vehicle body 230.

In the present embodiment, the air suspension system 100 having 2 air suspensions is described, but the number of air suspensions included in the air suspension system 100 is not particularly limited as long as it is 1 or more. The number of air suspensions can be equal to the number of wheels, for example. For example, in the case of a four-wheel vehicle, 2 air suspensions can be arranged on 2 front wheel sides and 2 air suspensions can be arranged on 2 rear wheel sides, for a total of 4 air suspensions. In the present embodiment, the example in which the air chambers 1C and 2C as the air springs are integrated with the air cylinders 1A and 2A for cushion is shown, but the air springs and the air cylinders (hydraulic cushions) 1A and 2A for cushion may be provided separately on the side of a large vehicle or a rear suspension as is well known.

[ air suspensions 1, 2]

In the air suspensions 1 and 2, air chambers 1C and 2C are formed between the damping cylinders 1A and 2A and the piston rods 1B and 2B, respectively, to constitute air springs. Passages described later are connected to the air chambers 1C and 2C, respectively, and the pressure and the vehicle height are controlled by the operation of the air suspension system 100.

[ compressor 3]

The compressor can compress air sucked from the suction port 3C and discharge the air from the discharge port 3D. Other details are described later.

[ intake air Filter 4]

The intake filter 4 is provided at an outdoor air intake port through which the air suspension system 100 can take outdoor air (atmosphere) as needed, and can remove dust and the like in the outdoor air when the air suspension system 100 takes the outdoor air.

[ tank 1 ] 5

The 1 st tank 5 can compress air by the compressor 3, for example, and store the compressed air. The pressure in the 1 st tank 5 can be detected by a pressure sensor 5B.

[ air dryer 7]

The air dryer 7 holds a desiccant such as silica gel therein, and the humidity of the air passing through the air dryer 7 can be reduced.

[ passage of air suspension System 100]

The air suspension system 100 includes, as passages, a supply/discharge passage 9, a supplement passage 6, an intake passage 20, a return passage 13, a bypass passage 16, and an exhaust passage 18.

(supply/discharge path 9)

The supply/discharge passage 9(9A, 9B, 9C) is a passage having a 1 st end at the air suspension 1, a 2 nd end at the air suspension 2, and a 3 rd end at the supply/discharge switching valve 10, and is provided with suspension control valves 11, 12.

The supply-discharge passage 9 has a distribution supply-discharge passage 9A, a distribution supply-discharge passage 9B, and a joint supply-discharge passage 9C, which are connected to each other at respective one ends at a distribution point 9N. The distribution supply discharge passage 9A has one end connected to the distribution point 9N and the other end connected to the air chamber 1C. The distribution supply discharge passage 9B has one end connected to the distribution point 9N and the other end connected to the air chamber 2C. The joint supply and discharge passage 9C has one end connected to the distribution point 9N and the other end connected to the supply and discharge switching valve 10.

(supplementary passage 6)

The makeup passage 6 is a passage having a 1 st end at the supply/discharge switching valve 10 and a 2 nd end at the discharge port 3D of the compressor 3, and is provided with a 1 st tank 5, an air dryer 7, and a 1 st check valve 8.

In the supplementary passage 6, the bypass terminal 16B is located on the opposite side of the ejection port 3D with respect to the air dryer 7. The 2 nd end of the bypass passage 16 described later is connected to the bypass end 16B.

In the replenishment passage 6, the exhaust start point 18A is located on the same side as the ejection port 3D with respect to the air dryer 7. The 1 st end of the exhaust passage 18 described later is connected to the exhaust start point 18A.

The 1 st canister 5 is located between the 1 st end of the make-up passage 6 and the 1 st check valve 8.

The air dryer 7 is located between the bypass terminal 16B and the exhaust gas start 18A. As will be described later, the air suspension system 100 can perform air discharge for discharging air in the air chambers 1C and 2C to the atmosphere by bypassing the compressor 3. At this time, since the air flows through the bypass passage 16 and the exhaust passage 18, the dry air in the air chambers 1C and 2C flows, and the moisture in the desiccant in the air dryer 7 can be removed.

The 1 st check valve 8 is located between the bypass destination 16B and the 1 st tank 5. The 1 st check valve 8 can flow air from the 2 nd end portion side to the 1 st end portion side of the replenishment path and block the flow in the opposite direction. This prevents the air in the 1 st tank 5 from flowing through the compressor 3 and the exhaust passage 18.

(suction side passage 20)

The suction-side passage 20 is a passage having a 1 st end at the suction port 3C and a 2 nd end at the outdoor-air intake port, and is provided with a 2 nd check valve 15.

The return terminus 13B is located between the suction port 3C of the suction-side passage 20 and the 2 nd check valve 15. The 2 nd end of the return passage 13 described later is connected to the return destination 13B.

The discharge destination 18B is located between the 2 nd check valve 15 and the outdoor air intake port. The 2 nd end of the exhaust passage 18 described later is connected to an exhaust terminal 18B.

The 2 nd check valve 15 is located between the return terminus 13B and the exhaust terminus 18B. The 2 nd check valve 15 can block the flow of air flowing from the 2 nd end portion side to the 1 st end portion side of the suction-side passage 20. As will be described in detail later, the air in the air chambers 1C and 2C passing through the return passage 13 and the return passage opening/closing valve 14 can be prevented from being discharged from the outdoor air intake port and can be guided to the suction port 3C.

(Return route 13)

The return passage 13 is a passage having a 1 st end at the supply/discharge switching valve 10 and a 2 nd end at the return end 13B, and is equipped with a return passage opening/closing valve 14.

In the return passage 13, a bypass starting point 16A is located between the supply-discharge switching valve 10 and the return passage opening-closing valve 14. The 1 st end of the bypass passage 16 described later is connected to the bypass starting point 16A.

(bypass passage 16)

The bypass passage 16 is a passage having a 1 st end at a bypass starting point 16A and a 2 nd end at a bypass ending point 16B, and is equipped with a 3 rd check valve 17.

The 3 rd check valve 17 can block the flow of air flowing from the 1 st end side to the 2 nd end side of the bypass passage 16. This enables the air ejected from the ejection port 3D to be efficiently guided to the 1 st tank 5.

(exhaust passage 18)

The exhaust passage 18 is a passage having a 1 st end portion at an exhaust start point 18A and a 2 nd end portion at an exhaust end point 18B, and is equipped with an exhaust passage opening and closing valve 19.

The exhaust passage 18 may be configured to discharge air from a place other than the outdoor air intake port without connecting the 2 nd end to the exhaust end point 18B, but if the exhaust end point 18B is provided between the outdoor air intake port and the 2 nd check valve 15 as described in this embodiment, dust adhering to the intake filter 4 can be removed by the air discharged through the return passage 13, the bypass passage 16, and the exhaust passage 18.

[ various valves of the air suspension system 100]

As described above, the air suspension system 100 has the supply/discharge switching valve 10, the 2 suspension control valves 11, 12, the return passage opening/closing valve 14, and the exhaust passage opening/closing valve 19 in addition to the check valves 8, 15, 17.

(supply/discharge switching valve 10)

The supply-discharge switching valve 10 is a three-way two-position electromagnetic valve that is connected to 3 passages and is capable of switching their connection relationship in 2 ways.

The supply-discharge switching valve 10 is connected to the 1 st end of the replenishment path 6, the 1 st end of the return path 13, and the 3 rd end of the supply-discharge path 9.

The supply/discharge switching valve 10 has, as 2 positions, a supply position (a) at which the 1 st end of the replenishment path 6 is connected to the 3 rd end of the supply/discharge path 9 and the 1 st end of the return path 13 is cut off from the 3 rd end of the supply/discharge path 9, and a discharge position (b) at which the 1 st end of the return path 13 is connected to the 3 rd end of the supply/discharge path 9 and the 1 st end of the replenishment path 6 is cut off from the 3 rd end of the supply/discharge path 9. The position can be switched by switching the excitation state of the solenoid 10A, for example. In the present embodiment, the supply/discharge switching valve 10 is held at the discharge position (B) by the spring 10B when the solenoid 10A is not excited, and is switched to the supply position (a) against the spring 10B when the solenoid 10A is excited.

(suspension control valve 11)

The suspension control valve 11 is provided between the distribution point 9N and the air suspension 1, and the suspension control valve 12 is provided between the distribution point 9N and the air suspension 2.

The suspension control valve 11 is a two-position two-way solenoid valve that is connected to 2 passages and is capable of switching their connection relationship in 2 ways.

The suspension control valve 11 has, as 2 positions, an open position (a) in which the distributed supply/discharge passage 9A is opened to enable supply/discharge of air from the air chamber 1C, and a closed position (b) in which the distributed supply/discharge passage 9A is closed to block supply/discharge of air from the air chamber 1C. The position can be switched by switching the excitation state of the solenoid 11A, for example. In the present embodiment, the suspension control valve 11 is held at the closed position (B) by the spring 11B when the solenoid 11A is not excited, and is switched to the open position (a) against the spring 11B when the solenoid 11A is excited.

(suspension control valve 12)

The suspension control valve 12 is a two-position two-way solenoid valve, similar to the suspension control valve 11, and can perform the same opening and closing control as the suspension control valve 11 with respect to the distribution supply/discharge passage 9B. The 2 suspension control valves 11 and 12 may be controlled simultaneously or independently. For this purpose, the suspension control valve 12 includes a solenoid 12A and a spring 12B.

(Return passage opening/closing valve 14)

The return passage opening/closing valve 14 is a two-position two-way electromagnetic valve, like the suspension control valves 11 and 12, and can perform opening/closing control between the bypass starting point 16A and the return end point 13B of the return passage 13, like the suspension control valves 11 and 12. For this purpose, the return passage opening/closing valve 14 includes a solenoid 14A and a spring 14B.

(exhaust passage opening/closing valve 19)

The exhaust passage opening/closing valve 19 is a two-position two-way electromagnetic valve, similar to the suspension control valves 11 and 12 and the return passage opening/closing valve 14, and can perform the same opening/closing control as the suspension control valves 11 and 12 and the return passage opening/closing valve 14 between the exhaust start point 18A and the exhaust end point 18B of the exhaust passage 18. For this purpose, the exhaust passage opening/closing valve 19 includes a solenoid 19A and a spring 19B.

(other arrangements of valves)

Further, the configuration may be modified so that the same number of supply/discharge switching valves 10 as the number of air suspensions, that is, two-position three-way valves, are used instead of the suspension control valves 11 and 12 provided in the supply/discharge passage 9. Specifically, the 1 st end of the replenishment path 6 is branched by the same number as the number of the air suspensions (2 in the present embodiment) and connected to each of the supply/discharge switching valves 10. The 1 st end of the return passage 13 is also branched by the same number as the number of the air suspensions, and connected to each of the supply/discharge switching valves 10. Further, one end of each distribution supply and discharge passage (2 in the present embodiment) is connected to each supply and discharge switching valve 10 instead of the distribution point 9N, respectively.

In the case where the configuration is changed as described above, it is also possible to exhaust the other air suspensions in the air suspension while supplying air to one or two or more of the air suspensions.

In addition, if the system configuration is simple, the suspension control valves 11 and 12 may be eliminated and a throttle may be provided in the distribution supply/discharge passage 9B.

Compressor 3 using linear motor 3B

Fig. 3 (a) is a cross-sectional view of the compressor 3 based on the yz plane, and fig. 3 (b) is a cross-sectional view of the compressor 3 based on the line a-a in fig. 3 (a), and is a z-direction view of the armature 50 and the mover 38.

The compressor 3 is composed of a compressor body 3A and a linear motor 3B.

(compressor body 3A)

The compressor body 3A has a cylinder 33, a piston 34 disposed slidably in the cylinder 33, a compression chamber 42 formed by the interior of the cylinder 33 and the piston 34, and a rod 47 having one end connected to the piston 34 and the other end connected to the connecting portion 35. The coupling portion 35 couples the rod 47 with the mover 36 of the linear motor 3B. The reciprocating power of the mover 36 is transmitted to the piston 34 via the coupling portion 35 and the rod 47.

The cylinder 33 has a substantially cylindrical side wall that matches the side peripheral shape (z-direction view shape) of the piston 34. An opening into which the piston 34 is inserted is provided on one side of the side wall in the z direction, and an inner wall on which the exhaust valve 31 and the intake valve 32 are formed is provided on the other side. A compression chamber 42 is formed as a space surrounded by the side wall, the piston 34, and the inner wall. The compression chamber 42 and the discharge port 3D are connected via the discharge valve 31. The compression chamber 42 and the suction port 3C are connected via the intake valve 32. As the exhaust valve 31, a valve or the like that allows only the flow from the compression chamber 42 to the discharge port 3D side and opens when the pressure in the compression chamber 42 is equal to or higher than a predetermined value can be used. As the intake valve 32, a valve or the like that allows only the flow from the intake port 3C to the compression chamber 42 and opens when the pressure in the compression chamber 42 is equal to or lower than another predetermined value can be used. The intake valve 32 and the exhaust valve 31 may be configured by electromagnetic valves capable of controlling the opening/closing timing of the valve body.

The piston 34 is reciprocated by the reciprocation power of the mover 36. The reciprocating direction of the piston 34 is defined as the z direction, and particularly the bottom dead center side of the piston 34 is defined as the + z direction and the top dead center side is defined as the-z direction. The piston 34 is connected to an end of the mover 36 in the-z direction via the rod 47 and the connecting portion 35, and the reciprocating movement of the mover 36 in the z direction moves the piston 34, thereby enabling the suction, compression, and discharge operations of air in the compression chamber 42.

Since the air in the compression chamber 42 is compressed or expanded in accordance with the movement of the piston 34, the pressure (air pressure) in the compression chamber 42 varies. The air pressure functions as an elastic body (air spring) that provides a force toward the bottom dead center to the piston 34.

(Linear motor 3B)

The linear motor 3B is a mechanism for applying reciprocating power to the mover 36, and as described in detail below, can facilitate the start-up of the compressor 3. The linear motor 3B includes an armature 50 having a core 41 and a coil 37 wound around the core 41, an end spacer 51, a magnetic spacer 52, a non-magnetic spacer 53, and a mover 36 to which a permanent magnet 38 is attached, and further includes a spring 40 as an elastic body which is an example of a biasing means.

< armature 50 >

The core 41 of the armature 50 is formed of a magnetic material, and has a shank 39 connecting the 1 st and 2 nd magnetic pole teeth 43A and 43B as the magnetic pole teeth 43 and 2 magnetic pole teeth 43.

The 1 st magnetic pole tooth 43A and the 2 nd magnetic pole tooth 43B face each other with a gap in which the mover 36 is mounted. The facing direction of the 1 st magnetic pole tooth 43A and the 2 nd magnetic pole tooth 43B is defined as the y direction. The 1 st magnetic pole tooth 43A and the 2 nd magnetic pole tooth 43B are connected by 2 shank portions 39. The 2 stems 39 each extend in the y direction and face each other with the mover 36 interposed therebetween. The opposing direction of the shank 39 is defined as the x-direction.

The core 41 may be formed by integrally forming the 1 st magnetic pole tooth 43A, the 2 nd magnetic pole tooth 43B, and the shank 39 as described in the present embodiment, or may be formed by forming a separate structure in the middle of the shank 39, for example. For example, the core 41 may be an object that can be divided into a portion having approximately half the y-direction dimension of the 1 st magnetic pole tooth 43A and the 2 nd shank portion 39, and a portion having approximately half the y-direction dimension of the 2 nd magnetic pole tooth 43B and the 2 nd shank portion 39.

The coil 37 of the armature 50 is wound around one or both of the 1 st magnetic pole tooth 43A and the 2 nd magnetic pole tooth 43B. An alternating current, for example, having a sine wave or rectangular wave shape flows through the coil 37. As a result, magnetic flux is generated from the coil 37, and as described later, magnetic force is generated between the magnetic flux and the permanent magnet 38 attached to the mover 36, and reciprocating power in the z direction can be applied to the mover 36. When the coil 37 is wound around both the 1 st magnetic pole tooth 43A and the 2 nd magnetic pole tooth 43B, the same-phase current flows through the coil 37.

The number of the armatures 50 is 1 or 2 or more (2 in the present embodiment) in the z direction. A magnetic spacer 52 formed of a magnetic material or a nonmagnetic spacer 53 formed of a nonmagnetic material can be provided between the armatures 50, but as described later, the magnetic spacer 52 is preferably used from the viewpoint of increasing the density of the magnetic flux. Further, for example, an end spacer 51 or a nonmagnetic spacer 53 made of a nonmagnetic material may be provided in the + z direction of the armature 50 located on the most + z direction side and in the-z direction of the armature 50 located on the most-z direction side, such as between the armature 50 and the compressor body 3A and between the armature 50 and a fixing portion 55 described later.

< spacer >

The end spacer 51, the magnetic spacer 52, and the nonmagnetic spacer 53 are members each having a certain degree of z-direction dimension and capable of adjusting the z-direction distance of the armatures 50 from each other or the armatures 50 from other members. The end spacer 51 has a shape that surrounds substantially all of the periphery of the connection portion 35 in the x direction and the y direction, and protects the connection portion 35 from the periphery. The end spacer 51 and the nonmagnetic spacer 53 suppress the magnetic flux generated by the armature 50 from leaking and propagating to the compressor body 3A and the spring 40, respectively. This allows the magnetic force to be effectively applied to the mover 36 by the magnetic flux generated by the armature 50. The armature 50, the end spacer 51, the magnetic spacer 52, the nonmagnetic spacer 53, and the fixing portion 55 are fixed to each other. This can be performed by, for example, inserting a bolt or the like through these members in the z direction.

< rotor 36 >

Fig. 4 is a plan view of the mover 36. The mover 36 includes a flat plate-like plate portion 36A having a width in the x direction and a longitudinal direction in the z direction, and 1 or 2 or more permanent magnets 38 attached to the plate portion 36A. Both the plate portion 36A and the permanent magnet 38 have a flat plate shape with the y direction as a normal vector. The permanent magnet 38 is magnetized in the y direction. In the case where a plurality of permanent magnets 38 are assembled, the permanent magnets 38 arranged in the z direction may be arranged such that the magnetization directions are alternately reversed.

As illustrated in fig. 3, the mover 36 is disposed between the 1 st magnetic pole tooth 43A and the 2 nd magnetic pole tooth 43B. That is, the 1 st magnetic pole tooth 43A is positioned on one side of the mover 36 in the y direction, and the 2 nd magnetic pole tooth 43B is positioned on the other side. The stem portions 39 are located on both sides of the mover 36 in the x direction.

The mover 36 has gaps 44A and 44B between the 1 st magnetic pole tooth 43A and the 2 nd magnetic pole tooth 43B, respectively, and similarly has a gap between itself and the shank 39.

The gaps 44A and 44B can be secured by, for example, adjusting the installation position of a linear guide (not shown) that guides the mover 36. The linear guides may be members having rolling bearings, or members provided on one side or both sides of the mover 36 in the y direction, for example. By securing the gaps 44A and 44B, friction generated in the mover 36 can be suppressed, and damping of the reciprocating power can be suppressed.

The coupling portion 35 is fixed to one end of the mover 36, and a support portion 54, which will be described later, is fixed to the other end.

< spring 40 >

The spring 40 provides the mover 36 with a force in the z-direction corresponding to a displacement from a neutral point (a displacement of the spring 40 at a natural length). One end of the spring 40 is fixed to a support portion 54 provided at the other end of the mover 36, and the other end is fixed to a fixing portion 55.

The support portion 54 is fixed to the other end of the mover 36, and is located on the opposite side of the armature 50 from the compressor main body 3A in the z direction. The fixing portion 55 is fixed to the vehicle 200, for example, directly or indirectly, and is located on the-z side of the support portion 54. The fixing portion 55 is fixed to the armature 50 via a nonmagnetic spacer 53, and the armature 50 is attached to a casing (not shown) of the compressor 3 and substantially stationary with respect to the vehicle 200. The armature 50 may be attached to the housing via vibration-proof rubber or the like.

Since the support portion 54 that moves relative to the armature 50 is located on the + z side of the fixed portion 55, the spring 40 is in a stretched state if the spring 40 is displaced to the + z side of the neutral point, and in a compressed state if the spring 40 is displaced to the-z side. In addition, the spring 40 of the present embodiment generates a spring force in the negative z direction if displaced to the + z side from the neutral point, and generates a spring force in the + z direction if displaced to the-z side, and acts on the mover 36. The neutral point can be configured as follows: between the displacement of the spring 40 when the displacement of the piston 34 is the top dead center and the displacement of the spring 40 when the displacement of the piston 34 is the bottom dead center. For example, the displacement of the spring 40 when the displacement of the piston 34 is the stroke center (the midpoint between the top dead center and the bottom dead center) may be set to substantially coincide with the neutral point, or may be set closer to the top dead center than the neutral point as described later.

For the sake of brevity, the displacement of the piston 34 may be used to refer to the displacement of the spring 40. For example, in the context of describing the displacement of the spring 40, the term "displacement of the spring 40 when the piston 34 is positioned at the top dead center, the bottom dead center, or the stroke center" may be used to indicate "the top dead center", "the bottom dead center", or "the stroke center".

< force by air pressure, magnetic force and spring force in driving >

Fig. 5 is a graph showing the relationship of the displacement of the piston 34, the force generated by the air pressure applied to the piston 34, the magnetic force, and the spring force with respect to the time t. The graph of fig. 5 (a) is a graph in which the vertical axis represents the displacement of the piston 34 and the horizontal axis represents time, and the graph of fig. 5 (b) is a graph in which the vertical axis represents force and the horizontal axis represents time. As described above, the force generated by the air pressure of the compression chamber 42, the magnetic force (electromagnetic force) generated by the armature 50 and the permanent magnet 38, and the force (spring force in the present embodiment) generated by the urging unit act on the piston 34.

Referring to fig. 5, the movement of the piston 34 from t equal to 0 (compression operation step) will be described assuming that the most expanded state of the compression chamber 42 (the state in which the piston 34 is at the bottom dead center) is t equal to 0. The way of advancing the time is the same in fig. 5 (a) and 5 (b). Note that a point at which z is 0 is the stroke center of the piston 34, a point belonging to a range where z < 0 is on the top dead center side, and a point belonging to a range where z > 0 is on the bottom dead center side. For convenience of explanation, the description will be made assuming that the stroke center coincides with the neutral point of the spring 40. Further, since the compressor 3 is reciprocated by the linear motor 3B without using the crank mechanism, the positions of the bottom dead center and the top dead center are not necessarily constant, but a case where the reciprocation of the piston 34 is stable and the top dead center and the bottom dead center are substantially constant will be described. During the period in which the stroke length varies, such as when the compressor 3 is started, the position at the time when the speed is 0 can be considered as the bottom dead center and the top dead center in each of the + z direction movement and the-z direction movement of the piston 34. In the compressor 3 of the present embodiment, the magnetic force applied to the mover 36 by the armature 50 is controlled such that the bottom dead center is located at a position in the + z direction with respect to the neutral point of the spring 40 and the top dead center is located at a position in the-z direction with respect to the neutral point of the spring 40.

< when at bottom dead center >)

When the piston 34 is at the bottom dead center, the spring 40 is displaced (stretched) toward the bottom dead center side from the neutral point, and therefore the piston 34 receives a large force toward the top dead center from the spring 40. Since the piston 34 is not displaced to the-z side from the bottom dead center, the magnitude of the spring force toward the top dead center is maximized.

The force generated by the air pressure at this time is a minimum value because the volume of the compression chamber 42 is the maximum. Further, although not particularly limited, since the force generated by the spring 40 is large, it is preferable to apply a known control method of the synchronous motor so that the force becomes a small force, preferably substantially 0, as illustrated in fig. 5 (b). In the present embodiment, a method for realizing such a magnetic force will be described later.

According to the above, the piston 34 at the bottom dead center receives a force toward the top dead center mainly by the spring 40.

< at bottom dead center side >

As the piston 34 moves from the bottom dead center toward the top dead center, the spring 40 is displaced from the stretched state to the natural length state, and therefore the spring force decreases. Further, the force generated by the air pressure at this time increases as the air in the compression chamber 42 is compressed. In addition, as for the magnetic force, it is preferable to apply a known control method of the synchronous motor so as to increase the force in the top dead center direction.

As described above, the piston 34 on the bottom dead center side receives a force toward the top dead center by the spring 40 and the magnetic force.

< when located at stroke center >)

The case where the piston 34 further moves toward the top dead center side and reaches the stroke center will be described. As described above, the description is made assuming that the stroke center coincides with the neutral point, but as described later, the neutral point does not necessarily need to coincide with the stroke center, and may be set to a position closer to the top dead center than the stroke center.

When the piston 34 is at the stroke center, the velocity of the mover 36 is highest and the displacement of the spring 40 is a natural length state, the spring force is the smallest. In addition, the force generated by the air pressure gradually increases. As for the magnetic force, a known control method of the synchronous motor is preferably applied so as to maximize the force in the top dead center direction.

< when at the side of top dead center >)

When the piston 34 exceeds the displacement 0 and the piston 34 reaches a position closer to the top dead center than the stroke center, the spring 40 is compressed, and the direction of the spring force is switched to the bottom dead center direction. In addition, the force generated by the air pressure gradually increases. The magnetic force can be delayed by, for example, 90 ° with respect to the displacement of the mover. In the present embodiment, as described later, the force in the top dead center direction is gradually reduced, and the force is gradually switched to the force in the bottom dead center direction.

As described above, the piston 34 on the top dead center side starts accumulating energy in the spring 40 and decelerates.

< when the position is near the top dead center >

When the piston 34 reaches the vicinity of the top dead center, the force in the direction toward the bottom dead center generated by the spring 40 gradually increases. Further, since the rate of decrease in the volume of the compression chamber 42 increases, the rate of increase in the pressure of the compression chamber 42 increases, and the force generated by the air pressure increases rapidly. As a trigger of the pressure increase in the compression chamber 42, the exhaust valve 31 opens to exhaust the air in the compression chamber 42, and therefore the force toward the bottom dead center generated by the air pressure becomes substantially constant and peaks. The magnetic force toward the top dead center side approaches 0 and reverses to switch to the bottom dead center side.

< when at top dead center >)

When the speed of the piston 34 is 0, the piston 34 reaches the top dead center. At this time, the spring 40 finishes the accumulation of energy to the piston 34 and is compressed to the maximum extent. The spring force in the bottom dead center direction and the force in the bottom dead center direction generated by the air pressure exceed the force in the top dead center direction, and the piston 34 is switched to the expansion operation step of moving at the speed toward the bottom dead center side. As described above, the compressor 3 receives the reciprocating power by the linear motor 3B, and therefore, the top dead center position is not necessarily constant.

< after switching to expansion operation process >

Since a pressure decrease due to the exhaust through the exhaust valve 31 and a pressure decrease due to an increase in the volume of the compression chamber 42 occur, the force in the bottom dead center direction generated by the air pressure sharply decreases. Further, since the spring 40 is close to the neutral point, the force in the bottom dead center direction by the spring 40 also gradually decreases. Further, the magnetic force is preferably configured such that the force in the bottom dead center direction gradually increases.

When the piston 34 moves in the bottom dead center direction to reach the stroke center, the spring force is 0. The force generated by the air pressure is also reduced. The magnetic force is preferably configured to be the largest in the bottom dead center direction.

When the piston 34 reaches a position closer to the bottom dead center side than the stroke center, the spring force is switched to the top dead center side, and the force generated by the air pressure is further reduced. The magnetic force is preferably configured such that the force in the bottom dead center direction gradually decreases.

When the force of the spring in the direction toward the top dead center and the force generated by the air pressure exceed the force in the direction toward the bottom dead center, the speed of the piston 34 becomes 0, the piston 34 reaches the bottom dead center. That is, the volume of the compression chamber 42 is maximized. Thereafter, the periodic operation can be repeated.

< relationship between Displacement and Each force >

Fig. 6 is a graph showing the relationship of the spring force applied to the piston 34, the force generated by the air pressure, and the magnetic force with respect to the displacement of the piston 34. The vertical axis represents the force applied to the piston 34, and the positive direction represents the force acting in the + z direction, and the negative direction represents the force acting in the-z direction. The intersection of the vertical axis and the horizontal axis is the origin, and the point at which z is 0 is the stroke center.

In fig. 6, a case where the neutral point of the spring 40 is located closer to the top dead center than the stroke center of the piston 34 is described, but when the neutral point of the spring 40 coincides with the stroke center of the piston 34, the same applies except that the straight line of the "spring force" in fig. 6 passes through the origin.

Since the force generated by the air pressure always applies a force in the + z direction to the piston 34, the stroke center of the piston 34 can be positioned on the-z side by setting the spring neutral point to the top dead center side with respect to the stroke center. That is, the stroke center of the piston 34 can be easily set to the center side of the z-direction dimension of the cylinder 33, and the maximum stroke length can be made longer.

< generation of magnetic force and magnetic circuit >

Fig. 7 is a sectional perspective view of the linear motor 3B of the present embodiment having 2 armatures 50 and the magnetic spacer 52 disposed therebetween.

A power supply including an inverter circuit and the like can be connected to the coil 37 wound around the magnetic pole tooth 43 of each armature 50, and a prescribed current can be passed. When the ac current or voltage is applied to the coil 37, a magnetic flux passing through the core 41, which is a magnetic body, is generated. The magnetic flux flows through a magnetic path including the shank 39, the 1 st magnetic pole tooth 43A, and the 2 nd magnetic pole tooth 43B, as illustrated by solid arrows as a magnetic path formed on the xy plane, for example. Thereby, the 1 st magnetic pole tooth 43A is magnetized to the N pole or the S pole, and the 2 nd magnetic pole tooth 43B opposed thereto is magnetized to the S pole or the N pole. By controlling the frequency and polarity of the current or voltage using various known synchronous motor methods, a magnetic repulsive force and a magnetic attractive force can be generated between the permanent magnet 38 and the magnetic pole teeth 43 mounted on the mover 36, and the z-direction reciprocating power can be supplied to the mover 36.

In the present embodiment, 2 armatures 50 arranged in the z direction are connected by magnetic spacers 52. The generated magnetic flux thus flows through a magnetic path including the 1 st and 2 nd magnetic pole teeth 43A and 43B of the 2 armatures 50 and the magnetic spacer 52 provided between the 21 st and 2 nd magnetic pole teeth 43A and 43B, respectively, as illustrated by a broken-line arrow as a magnetic path formed on the yz plane.

Thus, in the present embodiment, since 2 types of magnetic paths formed on 2 planes can be formed, saturation of magnetic flux can be suppressed. That is, the high-output linear motor 3B can be configured.

As illustrated in fig. 3 (a), the coils 37 are connected in such a manner that the directions of magnetic fluxes are opposite to each other between the armatures 50 adjacent to each other with the magnetic spacer 52 interposed therebetween, as indicated by 2 arrows 45.

When a current or a voltage is applied to the coil 37, magnetic attraction and magnetic repulsion acting on the mover 36 have y-direction components as illustrated by arrows 46A and 46B. Since the same kind of force as either the magnetic attraction force or the magnetic repulsion force acts on the permanent magnet 38 attached to the mover 36 between the magnetic pole teeth 43 on both sides in the y direction, the y-direction component of the magnetic force is substantially cancelled as a result.

< control of magnetic force >

As illustrated in fig. 7, focusing on the 2 armatures 50 arranged, let a be the z-coordinate of the magnetic pole tooth 43 on the-z direction side, C be the z-coordinate of the magnetic pole tooth 43 on the + z direction side, B be the z-coordinate of the midpoint between a and C, D be the z-coordinate of the midpoint between a and B, and E be the z-coordinate of the midpoint between B and C.

Next, the magnetic force in the z direction received by the 1 permanent magnet 38 attached to the mover 36 from the magnetized magnetic pole teeth 43 will be described. For the sake of simplicity, the permanent magnet 38 will be described as being magnetized so as to have an N pole in the + y direction and an S pole in the-y direction, but the same description is also true when the magnetization direction of the permanent magnet 38 is opposite.

When the center of the permanent magnet 38 in the z direction is located at a, the permanent magnet 38 does not receive a force in the z direction from the magnetic pole teeth 43 located at a, and when the center of the permanent magnet 38 in the z direction is located at C, the permanent magnet 38 does not receive a force in the z direction from the magnetic pole teeth 43 located at C. This is because the angle formed by the line passing through each of the magnetic pole teeth 43A and 43B and the permanent magnet 38 with the z-axis is 90 °.

When the z-direction center of the permanent magnet 38 is located at a, the permanent magnet 38 receives only a small force from the magnetic pole tooth 43 located at C, and when the z-direction center of the permanent magnet 38 is located at C, the permanent magnet 38 receives only a small force from the magnetic pole tooth 43 located at a. This is because the distance between the permanent magnet 38 and the magnetic pole teeth 43 is large.

For example, it is preferable that the timing when only 0 or a small force is applied, that is, the timing when the permanent magnet 38 is located at a or C substantially coincides with the timing when the spring force is large. That is, it is preferable to drive the compressor 3 by designing the spring constant of the spring 40, the magnitude of the current or voltage applied to the coil 37, and the like so that the position of the piston 34 substantially coincides with the top dead center when the permanent magnet 38 is located at a and the position of the piston 34 substantially coincides with the bottom dead center when the permanent magnet 38 is located at C. The current or voltage applied to the coil 37 when the permanent magnet 38 is positioned at a and C can be set to a small value, preferably substantially 0. The specific z-coordinate of the top dead center and the bottom dead center is not limited to this preferable embodiment, and can be adjusted as appropriate by designing the magnitude of the current or voltage applied to the coil 37.

When the center of the permanent magnet 38 in the z direction is located at B, the angle formed by the z axis and the straight line passing through the centers of the magnetic pole teeth 43 and the permanent magnet 38 located at a and C is, for example, about 45 °. In addition, the distance between the magnetic pole teeth 43 and the permanent magnet 38 is also small. Therefore, the permanent magnet 38 receives a force in the z direction to a large extent, and it is preferable to control the current or voltage applied to the coil 37 so that the force toward the top dead center is provided when the piston 34 is near the top dead center and the force toward the bottom dead center is provided when the piston is near the bottom dead center. That is, the compressor 3 is preferably configured such that B substantially coincides with the stroke center. The current or voltage applied to the coil 37 at this time can be set to a large value, preferably a peak value.

< starting of compressor 3 >

Fig. 8 is a view in which the magnetic force is removed from fig. 6.

When the compressor 3 is stopped, the mover 36 is at rest at a position where the forces applied to the mover 36 are equalized. Since the force generated by the air pressure is always applied to the piston 34 in the + z direction, when a compressor in which the linear motor 3B is not used as a motor for the compressor 3, for example, a compressor using a rotary motor and a crank mechanism is applied, when the compressor is stopped at or near the bottom dead center, it is necessary to apply a force in the top dead center direction, which is larger than the force generated by the air pressure, to the piston to the top dead center by using a current or voltage applied to the motor in order to start the compressor. Therefore, the current or voltage required for starting becomes large. With respect to the force generated by the air pressure, if the exhaust passage opening/closing valve 19 is set to the open position (a), the differential pressure between the suction port 3C and the discharge port 3D is reduced with time, and therefore, the start-up can be made easy, but if set to the closed position (b), the differential pressure is maintained, and therefore, the start-up is difficult to be made easy.

Since the compressor 3 of the present embodiment includes the linear motor 3B as the motor and the spring 40 as the biasing means, when the piston 34 receives a force toward the + z side by a force generated by the air pressure, the displacement of the spring 40 as the biasing means can be displaced toward the + z side from the neutral point. In this case, the spring 40 provides a force in the-z direction to the piston 34. As described in the present embodiment, when the fixing portion 55 is located on the-z side with respect to the support portion 54, the spring 40 provides a force in the-z direction in a stretched state. On the other hand, when the fixing portion 55 is located on the + z side with respect to the support portion 54, the spring 40 provides a force in the-z direction in a compressed state.

In this way, the force in the-z direction generated by the spring 40 partially or entirely cancels the force in the + z direction generated by the air pressure, and therefore, the compressor 3 can be easily started. Therefore, the position setting of the exhaust passage opening/closing valve 19 can be maintained at the closed position (b) until the next start of the compressor after the compressor is stopped, and therefore, the energy saving performance of the air suspension system 100 is improved, or the necessity of reducing the pressure of the air chambers 1C and 2C to start the compressor 3 is reduced, and therefore, the comfort of the occupant of the vehicle 200 can be improved.

A specific starting method will be explained. Before starting, the mover 36 is stationary at an equilibrium position of the force in the + z direction generated by the air pressure and the force in the-z direction generated by the urging unit. When an alternating current or voltage is applied to the coil 37, a magnetic force in the + z direction or the-z direction can be applied to the mover 36. Since the piston 34 is biased in the-z direction by the biasing means, the piston can reach the top dead center at the time of driving with a small amount of energy. Further, since the piston 34 can be balanced at the top dead center side with respect to the bottom dead center or the vicinity of the bottom dead center during the driving, the compressor 3 can be started even when a magnetic force is applied not only in the-z direction but also in the + z direction during the starting. In either case, compression or extension of the spring 40 and expansion or compression of the air in the compression chamber 42 occur in response to movement of the mover 36. As described later, by making the frequency of the alternating current or voltage substantially equal to the resonance frequency of the mover 36, energy is stored in the springs 40 and the air springs of the compression chambers 42, and the amplitude of the mover 36 gradually increases. Therefore, even under the condition that the pressure of the compression chamber 42 is high, the compressor 3 can be started with the current or voltage applied to the coil 37 being a small value.

The urging means is not limited to the spring 40 as a coil spring, and may be a plate spring, an elastic body such as rubber, or a potential energy applying portion such as an electromagnet, as long as it can apply a force to the mover 36 toward the top dead center when the compressor 3 is started.

< driving frequency of compressor 3 >

By making the resonance frequency of the mover 36 substantially equal to the frequency (drive frequency) of the alternating current flowing through the coil 37, the energy supplied to the mover 36 can be stored in the spring 40 and the like. This can increase the amplitude of the mover 36.

The resonance frequency of the mover 36 is roughly determined by the mass of the mover 36, the pressure in the compression chamber 42, the physical properties of the urging means, and the like, for example, the spring constant of the spring 40. If the mover 36 is operated so that the number of times per unit time (drive frequency) of the reciprocating motion of the mover 36 substantially matches the resonance frequency, the reciprocating motion of the mover 36 can be performed with less energy, and therefore the command signal to be sent to the coil 37 may be the resonance frequency.

[ operation of the air suspension System 100]

Next, the operation of the air suspension system 100 will be described with reference to fig. 1 and the like again.

(case of raising vehicle height)

Fig. 9 is a circuit configuration diagram of the air suspension system 100 showing the switching state of the valves when raising the body height of the vehicle 200. When the vehicle height is raised, for example, the pressure supply into the 1 st tank 5 is completed, and the return passage opening/closing valve 14 and the exhaust passage opening/closing valve 19 are held at the closed position (b) in a state where the compressor 3 is stopped. In this state, the supply/discharge switching valve 10 is switched to the supply position (a) by exciting the solenoid 10A of the supply/discharge switching valve 10, and the suspension control valves 11 and 12 are switched to the open position (a) by exciting the solenoids 11A and 12A of the suspension control valves 11 and 12.

Thereby, the compressed air in the 1 st tank 5 is led out to the supply/discharge passage 9, and is supplied into the air chambers 1C, 2C of the air suspensions 1, 2 through the supply/discharge passage 9. Thus, the vehicle height can be raised. When it is desired to supply air to only a part of the air suspensions 1 and 2, the suspension control valve corresponding to the air suspension to be supplied may be set to the open position (a) and the other suspension control valves may be set to the closed position (b). In the case where the load applied to each air suspension is not uniform, if so, fine vehicle height adjustment can be performed.

When the raising operation of the vehicle height is completed, the suspension control valves 11 and 12 are switched to the closed position (b). Accordingly, since the air chambers 1C and 2C of the air suspensions 1 and 2 are sealed, the air suspensions 1 and 2 can be maintained in the extended state and in the state in which the vehicle height is raised.

Further, the compressor 3 may be driven when the pressure in the 1 st tank 5 drops to or below a predetermined pressure during the vehicle height raising operation. When the pressure in the 1 st tank 5 is equal to or lower than a predetermined pressure at the time of starting the vehicle height raising operation, the pressure supply control described later may be performed while driving the compressor 3. Further, the pressure supply control described later may be performed while driving the compressor 3 regardless of the pressure in the 1 st tank 5.

(case of lowering vehicle height)

Fig. 10 is a circuit configuration diagram of the air suspension system 100 showing a valve switching state when the body height of the vehicle 200 is lowered. When the vehicle height is lowered, the supply/discharge switching valve 10 is held at the discharge position (b), and the exhaust passage opening/closing valve 19 is held at the closed position (b). In this state, the solenoid 14A of the return passage opening/closing valve 14 is excited to switch the return passage opening/closing valve 14 to the open position (a), and the solenoids 11A and 12A of the suspension control valves 11 and 12 are excited to switch the suspension control valves 11 and 12 to the open position (a). In addition, the compressor 3 is driven.

Thus, the air in the air chambers 1C, 2C of the air suspensions 1, 2 is led out to the return passage 13 through the distribution supply and discharge passages 9A, 9B and the joint supply and discharge passage 9C. The air led out to the return passage 13 is guided to the suction port 3C of the compressor 3 being driven by the return passage opening/closing valve 14, compressed by the compressor 3, and then stored in the 1 st tank 5 via the supplemental passage 6 and the air dryer 7. As a result, the vehicle height can be lowered by discharging air from the air chambers 1C and 2C. Further, if only a part of the suspension control valves 11 and 12 is set to the exhaust state, the air suspension of only the part can be reduced in size. In the case where the load applied to each air suspension is not uniform, if so, fine vehicle height adjustment can be performed.

After the lowering operation of the vehicle height is completed, the suspension control valves 11 and 12 are switched to the closed position (b). Accordingly, the distribution supply/ discharge passages 9A and 9B are closed to seal the air chambers 1C and 2C, and therefore the air suspensions 1 and 2 can be kept in a contracted state and can be kept in a state in which the vehicle height is lowered.

Since the compressed air of the air chambers 1C, 2C is supplied to the intake port 3C, when the supply/discharge switching valve 10 is in the exhaust position (b) and the return passage switching valve 14 is in the open position (a), the pressure of the intake port 3C can be estimated from the state of the open/close positions of the suspension control valves 11, 12 and the pressure in the air chambers 1C, 2C. Therefore, if the pressure sensors 1D and 2D connected to the suspension control valves 1 and 2 for measuring the pressures of the air chambers 1C and 2C are provided and the pressure information of the suspension control valve at the open position (a) is acquired, the spring constant of the air spring in the compression chamber 34 can be effectively estimated. In particular, the frequency of the current or voltage to be supplied to the coil 37 at the time of starting the compressor 3 can be effectively estimated.

(case of rapidly lowering vehicle height)

For example, when the vehicle height is rapidly lowered in order to stabilize the posture of the vehicle 200 during turning, the supply/discharge switching valve 10 is held at the discharge position (b), and the return passage opening/closing valve 14 is held at the closed position (b). In this state, the solenoid 19A of the exhaust passage opening/closing valve 19 is excited to switch the exhaust passage opening/closing valve 19 to the open position (a), and the solenoids 11A and 12A of the suspension control valves 11 and 12 are excited to switch the suspension control valves 11 and 12 to the open position (a). The compressor 3 is stopped.

In this case, the air in the air chambers 1C and 2C passes through the return passage 13, the bypass passage 16, and the exhaust passage 18 and is released from the outdoor air intake port to the atmosphere. As a result, air can be quickly discharged from the air chambers 1C, 2C, and the vehicle height can be quickly lowered.

When the vehicle height is rapidly lowered, the air discharged from the air suspensions 1 and 2 flows from the bypass passage 16 to the exhaust passage 18 through the air dryer 7. This enables moisture to be removed from the desiccant filled in the air dryer 7, and the desiccant can be regenerated.

(case of pressure-feeding to tank 1, 5.)

When the compressed air is released into the atmosphere or the like, the pressure in the 1 st tank 5 is low. In this case, the operation of increasing the pressure in the 1 st tank 5 can be performed. As illustrated in fig. 1, the compressor 3 is started in a state where the supply/discharge switching valve 10 is held at the discharge position (b), and the suspension control valves 11 and 12, the return passage opening/closing valve 14, and the exhaust passage opening/closing valve 19 are held at the closed positions (b), respectively.

Thereby, the compressor 3 sucks in outdoor air via the intake filter 4. The outdoor air flows into the compression chamber 42 from the suction port 3C through the suction-side passage 20, is compressed, and is discharged to the supplemental passage 6 from the discharge port 3D. The compressed air is dried by the air dryer 7 and then accumulated in the 1 st tank 5. Then, for example, when the pressure in the 1 st tank 5 reaches a certain pressure, the compressor 3 is stopped. This enables sufficient compressed air to be filled into the 1 st tank 5.

Since the exhaust passage opening/closing valve 19 and the return passage opening/closing valve 14 are in the closed position (b), the outdoor air sucked through the intake filter 4 can be efficiently advanced to the suction port 3C. In addition, since the supply/discharge switching valve 10 is the discharge position (b), the compressed air in the 1 st tank 5 can be prevented from being supplied to the air suspensions 1, 2.

According to the present embodiment, the linear motor 3B including the biasing means is used as the driving source of the compressor 3, so that the compressor 3 can be easily started from the equilibrium position of the mover 36 regardless of the pressure of the compression chamber 42. Therefore, since the starting can be performed with a small thrust, the air suspension system 100 using the compressor 3 having a small and simple structure can be provided. When the urging means is a spring, it may be a compression spring or an extension spring.

Example 2

The configuration of embodiment 2 can be the same as that of embodiment 1 except for the following.

Fig. 11 is a circuit diagram of the suspension system 100 of the present embodiment. In the suspension system 100 of the present embodiment, the 2 nd tank 71 is provided in the return passage 13. In the present embodiment, when the vehicle height is lowered or rapidly lowered, the compressed air of the air suspensions 1 and 2 can be accumulated in the 2 nd tank 71 without driving the compressor 3 by controlling the valves in the same manner as in fig. 10. Further, if the compressor 3 is started after the supply/discharge switching valve 10 is set to the discharge position (b), the return passage opening/closing valve 14 is set to the closed position (b), and the discharge passage opening/closing valve 19 is set to the closed position (b), and then the air in the 2 nd tank 71 is compressed by the compressor 3, the compressed air can be stored in the 1 st tank 5. Thereafter, the vehicle height is raised, whereby the compressed air in the 2 nd tank 71 can be supplied to the air suspensions 1 and 2.

Since the second tank 71 is provided in this embodiment, the pressure on the suction port 3C side can be made to exceed the atmospheric pressure, and therefore, the differential pressure between the suction port 3C and the discharge port 3D can be reduced. Therefore, the compressor 3 can be started more easily.

Further, a pressure sensor 71A for measuring the pressure of the 2 nd tank may be provided, and the information obtained by this pressure sensor 71A may be used to determine the driving frequency at the time of starting or driving the compressor 3 when the vehicle height is lowered, for example.

The present embodiment can also provide the same effects as embodiment 1.

Example 3

The configuration of embodiment 3 can be the same as that of embodiment 1 except for the following.

Fig. 12 is a circuit diagram of the suspension system 100 of the present embodiment. The air suspension system 100 of the present embodiment does not include a tank, and has an open circuit structure as follows: when the vehicle height is raised, air taken in from the atmosphere is compressed by the compressor 3, and the compressed air is directly sent to the air chambers 1C, 2C, and when the vehicle height is lowered, the compressed air in the air chambers 1C, 2C is directly opened to the atmosphere. Specifically, in contrast to embodiment 1, the return passage 13 is connected to the bypass passage 16, but is not connected to the suction-side passage 20.

The present embodiment can also provide the same effects as embodiment 1. Further, since air can be passed through the air dryer 7 during the exhaust, the air dryer 7 can be efficiently regenerated.

Example 4

The configuration of embodiment 4 can be the same as that of embodiment 3 except for the following.

Fig. 13 is a circuit diagram of the suspension system 100 of the present embodiment. The 1 st end of the exhaust passage 18 is connected to the supply-discharge switching valve 10, and the 2 nd end is open to the outdoor air. In comparison with embodiment 3, the return passage 13 and the bypass passage 16 are eliminated. Specifically, the outdoor air intake port, the 2 nd check valve 15, the compressor 3, the air dryer 7, the 1 st check valve 8, and the supply/discharge switching valve 10 are connected in this order, and are not connected to the discharge passage 18. Further, the exhaust passage 18 has one end opened to the supply/discharge switching valve 10 and the other end opened to the outdoor air, and is provided with an exhaust passage opening/closing valve 19. If this is done, the exhaust can be performed with a short passage length. The present embodiment can also provide the same effects as embodiment 1.

Example 5

The configuration of embodiment 5 can be the same as that of any of embodiments 1 to 4 except for the following.

Fig. 14 is a sectional side view based on the yz plane of the compressor 3 of the present embodiment. In the compressor 3, the spring 40 serving as the urging means includes a top dead center side spring 40C connected to the top dead center side of the mover 36 and a bottom dead center side spring 40E connected to the bottom dead center side. According to the present embodiment, by providing a plurality of biasing units, the influence of the biasing units can be increased when compared with the air spring of the compression chamber 42, and the compressor 3 can be started more easily. Alternatively, the springs 40 can be individually miniaturized.

The top dead center side spring 40C and the bottom dead center side spring 40E may be compression springs or tension springs, respectively. One may be a compression spring and the other may be an extension spring, or both may be compression springs or extension springs.

One of the top dead center side spring 40C and the bottom dead center side spring 40E is preferably used as the compression spring, and more preferably, both are used as the compression springs. Since the compression spring itself contacts the mover 36 and presses the mover 36 when the compression spring is about to return from the compressed state to the neutral point, the compression spring can be configured without firmly fixing the spring 40 to the support portion 54 or the like.

The present embodiment can also provide the same effects as embodiment 1.

Example 6

The configuration of the present embodiment can be the same as that of any of embodiments 1 to 5 except for the following.

Fig. 15 is a yz plane sectional view of the compressor 3 of the present embodiment, and fig. 16 is a graph showing a stroke command value L (a command value of the amplitude of the reciprocating motion of the mover 36 or the piston 34), a frequency command value ω of the voltage applied to the coil 37, and a relationship between the amplitude command value V of the applied voltage and time t in the entire normal state of the compressor 3 of the present embodiment from the time of startup. In the compressor 3, since the linear motor 3B is used as the motor, not only the frequency of the reciprocating motion of the piston 34 but also the stroke length can be appropriately set. In the drive control of the compressor 3, the target values of L and ω can be input and V can be calculated by a known motor control method. Using the calculated V, a voltage is applied from an inverter or the like to the coil 37.

The mover 36 is not provided with a biasing unit, and the mover 36 reciprocates mainly by receiving a magnetic force generated by the armature 50 in accordance with a current of the coil 37 flowing by an applied voltage determined by ω and V. The reciprocating amplitude does not necessarily coincide with the stroke command value L. The voltage command value V is calculated based on the stroke command value L, but in order to substantially match the actual stroke amount of the mover 36 with the stroke command value L, it is necessary to consider work generated by compression and expansion of air in the compression chamber 42 when calculating the voltage command value V. However, this is to enable a method or the like that considers only the magnetic force supplied to the mover 36 and does not consider the influence of the compression chamber 42 to be adopted. However, for the sake of simplicity of explanation, it is assumed that the stroke command value L matches the actual stroke of the piston 34.

In addition, the reciprocating frequency of the mover 36 follows in the same manner as ω, but cannot follow if ω is an excessively large value. This is because, when the direction of the magnetic force changes from the + z direction to the-z direction, for example, the mover 36 starts accelerating in the-z direction after decelerating the speed in the + z direction, and therefore the moving direction of the mover 36 is not immediately switched. If the direction of the magnetic force is switched in a time shorter than the time required for acceleration and deceleration, the mover 36 hardly moves and vibrates slightly.

As described below, in the present embodiment, the compressor 3 in the air suspension system 100 can be easily started.

L, ω, and V of the normal state of the compressor 3 (the state in which the piston 34 reciprocates in the state in which the discharge amount of the compressor 3 per unit time is substantially the same) are set to L °, ω, and V °, respectively. When starting the compressor 3, the initial value of the inputted stroke command value is designated as L smaller than L DEG₀. Preferably, the initial value of the frequency command value is further indicated as ω smaller than ω °₀. The initial value V of the voltage command value thus calculated₀Is a value less than V °. Thus, the voltage applied to coil 37 is a value less than V, and therefore, piston 34 is at L less than L₀Performing a reciprocating motion. That is, the compression step and the suction step can be alternately performed by a small stroke.

As described above, in the compressor 3 of the present embodiment, the linear motor 3B is used as the motor, and therefore, the stroke initial value L can be changed₀But is set to a small value. This can avoid performing the compression step over a large stroke, for example, L °, immediately after the start-up, and therefore, the compressor 3 can be easily started up. In this case, if the frequency command value ω is also set to be small, the length of movement of the piston 34 per unit time can be reduced, that is, the frictional force per unit time can be limited to a small value, and therefore, the compressor 3 can be started more easily, which is preferable.

The air suspension system 100 thereafter goes to, for example, a normal state, and can increase the stroke command value as neededL and a frequency command value ω. That is, the compressor 3 has a stroke L of the piston 34 which is larger than the stroke L of the piston 34 immediately after the start of the compressor₀A state where the driving is performed with a large stroke. Further, it is preferable that the compressor 3 has a frequency ω of the piston 34 which is higher than the frequency ω of the piston 34 immediately after the start of the compressor₀A state where the driving is performed at a large frequency. In the case where the biasing means is provided as in example 1 or the like, ω may be set to ω₀Set to a value less than the resonant frequency of the piston 34. That is, the frequency ω immediately after the start may be set to be smaller than the resonance frequency and thereafter increased to be the resonance frequency.

In the present embodiment, the voltage command value V to be supplied to the linear motor 3B is set small at the time of start and gradually increased, but the stroke command value L may be set small₀Set to L °. In this case, the voltage command value is V ° from immediately after the start, but the stroke of the piston 34 is a value smaller than L °. Specifically, the velocity is 0 at a point where the force generated by the air pressure and the magnetic force are approximately balanced, and after the magnetic force becomes the opposite direction, the movement in the opposite direction is started. This method also makes it possible to easily start the compressor 3 as described above. However, in this case, since an overcurrent may flow through the coil 37, it is preferable to provide a current limiter. In order to avoid the offset, it is preferable to set the frequency command value ω₀Starting from a low frequency and gradually increasing.

Here, in the case of a compressor using a crank mechanism as a comparative example, the stroke is uniquely determined according to the diameter of the centrifugal rotation of the crank mechanism. Here, the stroke of the compressor using the crank mechanism is represented as L °. When starting from the bottom dead center or the vicinity thereof, if the compression operation of about L ° cannot be performed from immediately after the start over the stroke from the start point to the top dead center, the start of the compressor is unsuccessful. That is, a force for continuing the compression operation over about L ° must be supplied from the motor, and the stroke length lo cannot be reduced. Therefore, it is necessary to provide a large motor capable of supplying a large current, for example.

Description of the symbols

1. 2 … air suspension; 3 … compressor; 4 … air intake filter; 5 … tank 1; 5B … pressure sensor; 6 … supplement the pathway; 8 … check valve 1; 9 … supply the discharge passage; 9A, 9B … distribute supply and discharge paths; 9C … supply the discharge path in combination; 10 … supply drain switching valve; 11. 12 … suspension control valve; 13 … return path; 14 … return passage opening and closing valve; 15 … No. 2 check valve; 16 … bypass path; 17 … check valve No. 3; 18 … exhaust passage; 19 … exhaust passage open/close valve; 33 … cylinder; 34 … a piston; 36 … mover; 37 … coil; 38 … permanent magnet; 40 … spring, 41 … iron core; 42 … compression chamber; 43 … magnetic pole teeth; 47 … bar; 51 … end spacers; 54 … support portion; 55 … fixing part; 71 … tank 2; 100 … air suspension system.

Claims (6)

1. An air suspension system which supplies air compressed by a compressor to a plurality of air chambers interposed between a vehicle body side and a wheel side and performs vehicle height adjustment in accordance with supply and discharge of the air,

the air suspension system is characterized by comprising:

an exhaust passage having a 1 st end connected to a discharge port side of the compressor and capable of discharging compressed air on the discharge port side; and

an exhaust passage opening/closing valve capable of realizing a closed position for shutting off the air flow of the exhaust passage and an open position for allowing the air flow of the exhaust passage,

the compressor has:

a mover coupled to the piston and extending in a moving direction of the piston;

an armature that reciprocates the mover in a moving direction of the piston; and

a force applying unit applying a force to the mover in a top dead center direction of the piston,

the urging means is a spring that applies a force to the piston on the side opposite to one side of the moving direction when the piston receives a force on the one side of the moving direction due to a pressure of air pressure,

the exhaust passage opening/closing valve is set to a closed position until the next start of the compressor after the compressor is stopped.

2. The air suspension system of claim 1,

the urging means is a spring which is displaced to a neutral point when having a natural length, is compressed when the piston is positioned on a top dead center side from the neutral point in accordance with the reciprocating motion of the piston, and is extended when the piston is positioned on a bottom dead center side from the neutral point,

the neutral point of the spring is closer to the top dead center than the piston is located at the stroke center of the reciprocating motion.

3. An air suspension system having:

a plurality of air chambers interposed between a vehicle body side and a wheel side, and configured to adjust a vehicle height according to supply and discharge of air;

a compressor that compresses air; and

a tank for accumulating the air compressed by the compressor,

storing air compressed by the compressor in the tank and supplying the air in the tank to the air chamber,

the air suspension system is characterized by comprising:

an exhaust passage having a 1 st end connected to a discharge port side of the compressor and capable of discharging compressed air on the discharge port side; and

an exhaust passage opening/closing valve capable of realizing a closed position for shutting off the air flow of the exhaust passage and an open position for allowing the air flow of the exhaust passage,

the compressor has:

a mover coupled to the piston and extending in a moving direction of the piston;

an armature that reciprocates the mover in a moving direction of the piston; and

a force applying unit applying a force to the mover in a top dead center direction of the piston,

the urging unit is a spring that applies a force to the piston on an opposite side to one side of the moving direction when the piston receives the force on the one side due to a pressure of air pressure,

the exhaust passage opening/closing valve is set to a closed position until the next start of the compressor after the compressor is stopped.

4. The air suspension system of claim 3,

the compressor has a state in which, when air in the air chamber is discharged, the air in the air chamber is compressed and supplied to the tank.

5. The air suspension system of claim 3,

a pressure sensor for detecting pressure information of air in the tank or the air chamber,

the pressure information is used when determining a driving frequency for starting the compressor.

6. The air suspension system of claim 3,

the urging means is a spring which is displaced to a neutral point when having a natural length, is compressed when the piston is positioned on a top dead center side from the neutral point in accordance with the reciprocating motion of the piston, and is extended when the piston is positioned on a bottom dead center side from the neutral point,

the neutral point of the spring is closer to the top dead center than the piston is located at the stroke center of the reciprocating motion.

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